Methods of and systems for synchronized coordination of energy balancing and system time in the control of bulk power transfers

Claim 2

An improved control system for a multiple-area interconnected electric power system including means for measuring the net interchange for each area, means for setting the net interchange schedule for each area, means for determining the inadvertent interchange accumulations in each area measured over a span of time common to all areas; means for setting the time period common to all areas within which inadvertent interchange accumulations are to be corrected, means for setting the frequency bias for each area, means for measuring the system steady state frequency, means for setting the system steady state frequency schedule, means for setting the time-error bias common to all areas, means for determining the accumulated system timeerror, means coupled to the aforesaid means for generating control signals for the respective areas, and regulating means responsive to the control signals to regulate the generation of power in the respective areas so that the respective control signals are reduced toward zero causing each area to operate on net interchange tie-line bias control modified to correct for inadvertent interchange accumulations and time-error accumulation, the improvement comprising: means for maintaining the time-error bias setting inversely proportional to and of opposite polarity from the time period within which inadvertent interchange accumulations are to be corrected such that correction of inadvertent interchange and time-error is substantially confined to the particular areas of the system which respectively caused the inadvertent interchange accumulations and time-error accumulations, frequency-bias power assistance to an area of the system which is at fault or in need is not curtailed or denied by other areas which are in a position to supply such assistance, the average interchange of power over the tie-lines interconnecting the areas, when there are no prevailing net interchange measuring or schedule setting errors or frequency measuring or schedule setting errors and no prevailing errors in determining area inadvertent interchange and no regulating errors, is substantially maintained on a predetermined schedule so as to reduce toward zero accumulated inadvertent interchange, and simultaneously in the same time span, the average frequency of the system as a whole is substantially maintained so as to reduce toward zero accumulated time-error, and the accumulated inadvertent interchange of each area, when there are prevailing net interchange measuring or schedule setting errors or frequency measuring or schedule setting errors or prevailing errors in determining area inadvertent interchange but no regulating errors, is substantially maintained at a predetermined and unique value and simultaneously in the same time span, the accumulated time error of the system as a whole is substantially maintained at a predetermined and unique value as will, for each area and for the system as a whole, counterbalance the effects of said prevailing errors, and will cause area power interchanges and system frequency to return to and be substantially maintained at their respective scheduled values.

Claim 3

The improved control system of claim 1, wherein the time error bias in Hz. per second is maintained substantially equal to and of opposite polarity from the standard system frequency divided by the product of 3,600 and the time period, expressed in hours, within which inadvertent interchange accumulations are to be corrected, when the power quantities are expressed in megawatts, energy quantities in megawatt hours, frequency quantities in Hz., time error in seconds, and the frequency bias in megawatts per 0.1 Hz.

Claim 4

The improved control system of claim 1, wherein the time error bias expressed in reciprocal hours is maintained substantially equal to and of opposite polarity from the reciprocal of the time period, expressed in hours, within which inadvertent interchange accumulations are to be corrected, when the power quantities are expressed in megawatts, energy quantities in megawatt hours, frequency quantities in Hz., time error as the time integral of the frequency deviation in Hz. hours, and the frequency bias in megawatts per 0.1 Hz.

Claim 5

An improved control system for a multiple-area interconnected electric power system including local means for measuring the net interchange for each area, local means for setting the net interchange schedule for each area, local means for determining the inadvertent interchange accumulations in each area measured over a span of time common to all areas; local means for setting the time period common to all areas within which inadvertent interchange accumulations are to be corrected, local means for setting the frequency bias for each area, central means for measuring the system steady state frequency, central means for setting the system steady state frequency schedule, central means for setting the time-error bias common to all areas, central means for determining the accumulated system time-error, central means for broadcasting for use in each area a broadcast signal representing the system steady state frequency, the system steady state frequency schedule, the time-error bias common to all areas and the accumulated system time-error, means coupled to the aforesaid local means and responsive to said broadcast signal for generating control signals for the respective areas, and regulating means responsive to the control signals to regulate the generation of power in the respective areas so that the respective control signals are reduced toward zero causing each area to operate on net interchange tie-line bias control modified to correct for inadvertent interchange accumulations and time-error accumulation, the improvement comprising: means for maintaining the time-error bias setting inversely porportional to and of opposite polarity from the time period within which inadvertent interchange accumulations are to be corrected such that correction of inadvertent interchange and time-error is substantially confined to the particular areas of the system which respectively caused the inadvertent interchange accumulations and time-error accumulations, frequency-bias power assistance to an area of the system which is at fault or in need is not curtailed or denied by other areas which are in a position to supply such assistance, the average interchange of power over the tie-lines interconnecting the areas when there are no prevailing net interchange measuring or schedule setting errors or frequency measuring or schedule setting errors and no prevailing errors in determining area inadvertent interchange and no regulating errors, is substantially maintained on a predetermined schedule so as to reduce toward zero accumulated inadvertent interchange, and simultaneously in the same time span, the average frequency of the system as a whole is substantially maintained so as to reduce toward zero accumulated time-error, and the accumulated inadvertent interchange of each area, when there are prevailing Net interchange measuring or schedule setting errors or frequency measuring or schedule setting errors or prevailing errors in determining area inadvertent interchange but no regulating errors, is substantially maintained at a predetermined and unique value and simultaneously in the same time span, the accumulated time error of the system as a whole is substantially maintained at a predetermined and unique value as will, for each area and for the system as a whole, counterbalance the effects of said prevailing errors, and will cause area power interchanges and system frequency to return to and be substantially maintained at their respective scheduled values.

Claim 6

An improved control system for a multiple-area interconnected electric power system including local means for measuring the net interchange for each area, local means for setting the net interchange schedule for each area, local means for determining the inadvertent interchange accumulations in each area measured over a span of time common to all areas; local means for setting the time period common to all areas within which inadvertent interchange accumulations are to be corrected, local means for setting the frequency bias for each area, central means for measuring the system steady state frequency, central means for setting the system steady state frequency schedule, central means for setting the time-error bias common to all areas, central means for determining the accumulated system time-error, central means for broadcasting for use in each area a broadcast signal representing the system steady state frequency, the system steady state frequency schedule, the time-error bias common to all areas and the accumulated system time-error, means coupled to the aforesaid local means and responsive to said broadcast signal for generating control signals for the respective areas, and regulating means responsive to the control signals to regulate the generation of power in the respective areas so that the respective control signals are reduced toward zero causing each area to operate on net interchange tie-line bias control modified to correct for inadvertent interchange accumulations and time-error accumulation, the improvement comprising: means for maintaining the time-error bias setting inversely porportional to and of opposite polarity from the time period within which inadvertent interchange accumulations are to be corrected such that correction of inadvertent interchange and time-error is substantially confined to the particular areas of the system which respectively caused the inadvertent interchange accumulations and time-error accumulations, frequency-bias power assistance to an area of the system which is at fault or in need is not curtailed or denied by other areas which are in a position to supply such assistance, the average interchange of power over the tie-lines interconnecting the areas when there are no prevailing net interchange measuring or schedule setting errors or frequency measuring or schedule setting errors and no prevailing errors in determining area inadvertent interchange and no regulating errors, is substantially maintained on a predetermined schedule so as to reduce toward zero accumulated inadvertent interchange, and simultaneously in the same time span, the average frequency of the system as a whole is substantially maintained so as to reduce toward zero accumulated time-error, and the accumulated inadvertent interchange of each area, when there are prevailing Net interchange measuring or schedule setting errors or frequency measuring or schedule setting errors or prevailing errors in determining area inadvertent interchange but no regulating errors, is substantially maintained at a predetermined and unique value and simultaneously in the same time span, the accumulated time error of the system as a whole is substantially maintained at a predetermined and unique value as will, for each area and for the system as a whole, counterbalance the effects of said prevailing errors, and will cause area power interchanges and system frequency to return to and be substantially maintained at their respective scheduled values.

Claim 7

The improved control system of claim 4 wherein the improvement further comprises central means for transmitting a signal representing the time period within which inadvertent interchange accumulations are to be corrected to each of said local means for setting the time period common to all areas within which inadvertent interchange accumulations are to be corrected.

Claim 8

The improved control system of claim 4, wherein the time error bias in Hz. per second is maintained substantially equal to and of opposite polarity from the standard system frequency divided by the product of 3,600 and the time period, expressed in hours, within which inadvertent interchange accumulations are to be corrected, when the power quantities are expressed in megawatts, energy quantities in megawatt hours, frequency quantities in Hz., time error in seconds, and the frequency bias in megawatts per 0.1 Hz.

Claim 9

The improved control system of claim 4, wherein the time error bias expressed in reciprocal hours is maintained substantially equal to and of opposite polarity from the reciprocal of the time period expressed in hours, within which inadvertent interchange accumulations are to be corrected, when the power quantities are expressed in megawatts, energy quantities in megawatt hours, frequency quantities in Hz., time error as the time integral of the frequency deviation in Hz. hours, and the frequency bias in megawatts per 0.1 Hz.

Claim 10

An improved method of controlling a multiple-area interconnected electric power system including the steps of measuring the net interchange for each area, setting the net interchange schedule for each area, determining the inadvertent interchange accumulations in each area measured over a span of time common to all areas, setting the time period common to all areas within which inadvertent interchange accumulations are to be corrected, setting the frequency bias for each area, measuring the system steady state frequency, setting the system steady state frequency schedule, setting the time-error bias common to all areas, determining the accumulated system time-error, generating signals representing the aforesaid measurements, settings and determinations or combinations thereof, generating control signals for the respective areas in response to the aforesaid signals, and automatically regulating the generation of power in the respective areas so that the respective control signals are reduced toward zero causing each area to operate on net interchange tie-line bias control modified to correct for inadvertent interchange accumulations and time-error accumulation, the improvement comprising the additional step of: maintaining the time-error bias setting inversely proportional to and of opposite polarity from the time period within which inadvertent interchange accumulations are to be corrected.

Claim 11

An improved method of controlling a multiple-area interconnected electric power system including the steps of measuring the net interchange for each area, setting the net interchange schedule for each area, determining the inadvertent interchange accumulations in each area measured over a span of time common to all areas, setting the time period common to all areas within which inadvertent interchange accumulations are to be corrected, setting the frequency bias for each area, measuring the system steady state frequency, setting the system steady state frequency schedule, setting the time-error bias common to all areas, determining the accumulated system time-error, generating signals representing the aforesaid measurements, settings and determinations or combinations thereof, generating control signals for the respective areas in response to the aforesaid signals, and automatically regulating the generation of power in the respective areas so that the respective control signals are reduced toward zero causing each area to operate on net interchange tie-line bias control modified to correct for inadvertent interchange accumulations and time-error accumulation, the improvement comprising the additional step of: maintaining the time-error bias setting inversely proportional to and of opposite polarity from the time period within which inadvertent interchange accumulations are to be corrected.

Claim 12

The improved method of claim 8 including the step of substantially confining the correction of inadvertent interchange and time-error to the particular areas of the system which respectively caused the inadvertent interchange accumulations and time-error accumulations.

Claim 13

The improved method of claim 8 including the step of preventing the curtailment or denial of frequency-bias power assistance to an area of the system which is at fault or in need by other areas which are in a position to supply such assistance.

Claim 14

The improved method of claim 8 including the step of, when there are no prevailing net interchange measuring or schedule setting errors or frequency measuring or schedule setting errors and no prevailing errors in determining area inadvertent interchange and no regulating errors, substantially maintaining the average interchange of power over the tie-lines interconnecting the areas on a predetermined schedule so as to reduce toward zero accumulated inadvertent interchange, and simultaneously in the same time span, substantially maintaining the average frequency of the system as a whole so as to reduce toward zero accumulated time-error.

Claim 15

The improved method of claim 8 comprising the additional step of, when there are prevailing net interchange measuring or schedule setting errors or frequency measuring or schedule setting errors or prevailing errors in determining area inadvertent interchange but no regulating errors, substantially maintaining the accumulated inadvertent interchange of each area at a predetermined and unique value and simultaneously and in the same time span, substantially maintaining the accumulated time error of the system as a whole at a predetermined and unique value as will, for each area and for the system as a whole, counterbalance the effects of said prevailing errors, and will cause area power interchanges and system frequency to return to and be maintained at their respective scheduled values.

Claim 16

The improved method of claim 8 wherein the time error bias in Hz. per second is maintained substantially equal to and of opposite polarity from the standard system frequency divided by the product of 3,600 and the time period, expressed in hours, within which inadvertent interchange accumulations are to be corrected, when the power quantities are expressed in megawatts, energy quantities in megawatt hours, frequency quantities in Hz., time error in seconds, and the frequency bias in magawatts per 0.1 Hz.

Claim 17

The improved method of claim 8, wherein the time error bias expressed in reciprocal hours is maintained substantially equal to and of opposite polarity from the reciprocal of the time period, expressed in hours, within which inadvertent interchange accumulations are to be corrected, when the power quantities are expressed in megawatts, energy quantities in megawatt hours, frequency quantities in Hz., time error as the time integral of the frequency deviation in Hz. hours, and the frequency bias in megawatts per 0.1 Hz.